Camel milk products beyond yoghurt and fresh milk: challenges, processing and applications.

Camel (Camelus dromedarius and (Camelus bactrianus) are commonly domesticated in the arid and semi-arid regions because they are well adapted to live in harsh climatic conditions. Camel milk is widely consumed in these regions due to its high nutritional value and medicinal properties. It is rich in protein, minerals and vitamins. Moreover, it possesses therapeutic properties such as anti-microbial, anti-oxidants, anti-viral and anti-cancer. Camel milk can be processed into value added products with the aim of extending shelf life and diversifying its usage. However, there are various challenges experienced in processing of camel milk products. This study aims at reviewing published literature on camel milk products processing, processing challenges, the available solutions and applications. To achieve these aims, literature search was carried out using narrative methodology. Literature review provided information concerning processing of camel milk products, the challenges, how to overcome these processing challenges and applications. From this review of literature on camel milk products it can be concluded that it's possible to process these products with some challenges but scientific and technological solutions are available that are improving over time.

Production and characterisation of camel milk yoghurt containing different types of stabilising agents.

As at 2020, Kenya was the best performing camel milk producer globally, with an annual production of 1.125 million tonnes. Despite the high production, about 50% of milk is wasted due to challenges affecting value addition to products such as yoghurt. The production of camel milk yoghurt faces multiple challenges, such as poor texture and weak structure, resulting in poor consumer acceptability. This study aimed to improve the physicochemical properties of camel milk yoghurt by adding different stabilising agents and calcium chloride. Yoghurt samples were processed using 3 L of camel milk, 6% sugar, 0.006% starter cultures, corn starch or modified starch and calcium chloride. The stabilisers were added at 2, 2.5, and 3% and Calcium Chloride at 0.075%. The milk was pasteurised at 90 °C for 30 min. Fermentation was performed for 6 h at 42 ±1 °C, and yoghurt was stored at 4 °C. The total titratable acidity, pH and viscosity were monitored hourly during fermentation and storage, while syneresis and water holding capacity were analysed at 1, 7, 14 and 21 days of refrigerated storage. The sensory evaluation was done using the 9-point hedonic scale to rate yoghurt samples' overall acceptability, colour, sweetness and thickness. The TTA of camel milk yoghurt increased with increasing fermentation time (0-6 h) and storage time from 1 to 21 days. The pH decreased with increasing fermentation time (0-6 h) and storage time from 1 to 21 days. The addition of stabilisers increased the viscosity of the yoghurt, with 3% corn starch exhibiting the highest viscosity throughout the fermentation and storage time. Corn starch had a higher effect on viscosity compared to modified starch. Calcium chloride further amplified the viscosity of the yoghurt. The addition of stabilisers reduced syneresis by over 44% compared to bovine yoghurt. In this study, the best results of viscosity, syneresis and sensory evaluation were observed when stabilising agents were added at the rate of 2.5% modified starch and 0.075% Calcium chloride.

Lactic Acid Bacteria from African Fermented Cereal-Based Products: Potential Biological Control Agents for Mycotoxins in Kenya.

Cereals play an important role in global food security. Data from the UN Food and Agriculture Organization projects increased consumption of cereals from 2.6 billion tonnes in 2017 to approximately 2.9 billion tonnes by 2027. However, cereals are prone to contamination by toxigenic fungi, which lead to mycotoxicosis. The current methods for mycotoxin control involve the use of chemical preservatives. However, there are concerns about the use of chemicals in food preservation due to their effects on the health, nutritional quality, and organoleptic properties of food. Therefore, alternative methods are needed that are affordable and simple to use. The fermentation technique is based on the use of microorganisms mainly to impart desirable sensory properties and shelf-life extension. The lactic acid bacteria (LAB) are generally regarded as safe (GRAS) due to their long history of application in food fermentation systems and ability to produce antimicrobial compounds (hydroxyl fatty acids, organic acids, phenyllactic acid, hydrogen peroxide, bacteriocins, and carbon dioxide) with a broad range of antifungal activity. Hence, LAB can inhibit the growth of mycotoxin-producing fungi, thereby preventing the production of mycotoxins. Fermentation is also an efficient technique for improving nutrient bioavailability and other functional properties of cereal-based products. This review seeks to provide evidence of the potential of LAB from African fermented cereal-based products as potential biological agents against mycotoxin-producing fungi.

Fermentation of African nightshade leaves with lactic acid bacterial starter cultures.

The interest in the consumption of African indigenous leafy vegetables increased in African countries, e.g. Kenya, within the last years. One example of African indigenous leafy vegetables is African nightshade (Solanum scabrum) which is nutritious, rich in proteins and micronutrients and therefore could contribute to a healthy diet. African nightshade has several agricultural advantages. However, the most important disadvantage is the fast perishability which leads to enormous post-harvest losses. In this study, we investigated the fermentation of African nightshade as a post-harvest processing method to reduce post-harvest losses. The two lactic acid bacterial starter strains Lactiplantibacillus plantarum BFE 5092 and Limosilactobacillus fermentum BFE 6620 were used to inoculate fermentations of African nightshade leaves with initial counts of 106-107 cfu/ml. Uninoculated controls were conducted for each fermentation trial. Fermentations were performed both in Kenya and in Germany. The success of the inoculated starter cultures was proven by the measurement of pH values and determination of lactic acid concentration. Lactobacilli strains dominated the microbiota of the starter inoculated samples in contrast to the non-inoculated controls. This was supported by classical culture-dependent plating on different microbiological media as well as by the culture-independent molecular biological methods denaturing gradient gel electrophoresis and 16S rRNA gene high-throughput amplicon sequencing. We could demonstrate that the use of the selected starter cultures for fermentation of African nightshade leaves led to controlled and reliable fermentations with quick acidification. Thus, controlled fermentation with appropriate starter cultures is a promising method for post-harvest treatment of African nightshade leaves.

Effect of Lb. plantarum BFE 5092 Fermentation on Antinutrient and Oligosaccharide Composition of Whole Red Haricot Bean (Phaseolus vulgaris L).

Common beans are a leguminous plant of the genus Phaseolus. They are rich in protein, energy, and minerals. They confer a wide range of health benefits when consumed. Utilization of common bean has however been poor due to high antinutrient content that results in reduced nutrient digestibility and mineral bioavailability. Flatulence after consumption is also a huge deterrent to common bean consumption. Lactic acid fermentation is the most common form of food fermentation with the Lactobacilli spp dominating most spontaneous fermentations. The objective of this study was to determine the effect of lactic acid bacteria (LAB) on the antinutrient and flatulence causing oligosaccharide composition of red haricot bean. A factorial research design was used in the study. Red haricot beans were sorted and soaked for 15 h. The soaked beans were fermented in 2% salt-sugar solutions for 120 h. Experimental batch was inoculated with Lb. plantarum BFE 5092 (IF), and the control batch was spontaneously fermented (SF). Microbial growth and pH were monitored every 24 h during fermentation. After fermentation, the beans were dried and milled, and the flours were subjected to biochemical analysis. ANOVA was done using SPSS statistics 23. The pH decreased significantly (P < 0.05) from 6.06 to 3.9 in both batches at the end of fermentation. The LAB counts significantly increased (P < 0.05) in both batches, whereas coliform counts decreased significantly (P < 0.05). Fungi were not detected in both batches. Soaking lowered tannins and phytates and raffinose concentrations significantly but had no significant effect on stachyose concentration. At the end of 120 h of fermentation, the tannin content was 109.50 and 54.04 mg/100 g in IF and SF, respectively. Phytates were at 242.52 and 163.43 mg/100 g in IF and SF, respectively. Raffinose content was 32.85 and 32.58 mg/100 g in IF and SF, respectively, while stachyose content was 593.33 and 467.49 mg/100 g in IF and SF, respectively. This research showed that LAB is able to ferment soaked whole red haricot and lower the tannin, phytate, raffinose, and stachyose content significantly. Spontaneous fermentation lowered these antinutrients and oligosaccharides better than inoculation with Lb. plantarum BFE 5092.

Influence of physicochemical parameters on storage stability: Microbiological quality of fresh unpasteurized fruit juices.

Fresh juices rich in health and nutritional benefits are valued for their fresh flavor, taste, and aroma. These juices' quality however is affected by factors like temperature, light, and microbiological contamination significantly changing physicochemical parameters and storage stability. Physicochemical and microbiological analyses of passion fruit, pineapple, and mango juices in dark and light bottles at 24°C and 4°C were conducted in Kampala, Uganda for 12 days. Physicochemical parameters significantly reduced (p < .05) storage stability of fresh juices, while no significant changes (p > .05) were observed for the microbiological analyses. pH values ranged from 3.0 to 4.2 (dark) bottles and 2.9 to 4.0 (light) bottles for juices at 24°C and 4°C. °Brix values were from 1.0 to 5.5 for dark and clear bottles at 24°C and 4°C. TTA (%) values ranged from 1.1 to 7.2 (dark) bottles and 1.1 to 7.4 for (light) bottles at 24°C and 4°C. Ascorbic acid content ranged from 3.5 to 61.0 mg/ 100 ml and 5.5 to 56.7 mg/100 ml for juices in dark and clear bottles, respectively. total plate counts ranged from 1.3 × 10___ to 3.3 × 107 CFU/ml (dark bottles at 24°C) to 3.5 × 10³ to 3.3 × 108 CFU/ml (dark bottles at 4°C). For juices in light bottles, total plate counts ranged from 1.8 × 10___ to 8.0 × 107 CFU/ml (24°C) and 2.7 × 10___ to 1.5 × 108 CFU/ml (4°C). High microbial loads suggest the use of poor processing techniques and lack of good hygiene which lower quality and reduce storage stability of juices. Storage temperature greatly reduces physicochemical parameters both at ambient and refrigeration temperatures. This implies that temperature control for unpasteurized juices is critical in order to inhibit microorganism metabolic activities which accelerate biodeterioration leading to spoilage and short shelf life. Fresh unpasteurized juices stored at 24°C and 4°C may safely be consumed within 1 and 2 days, respectively.

Draft Genome Sequence of Lactobacillus fermentum BFE 6620, a Potential Starter Culture for African Vegetable Foods, Isolated from Fermented Cassava.

We report the draft genome sequence of Lactobacillus fermentum BFE 6620 from fermented cassava used as a potential starter culture for African vegetable fermentation. Sequence analysis showed the assembled genome size to be 1,982,893 bp, encoding a predicted total of 2,003 protein-coding genes, 14 rRNAs, 54 tRNAs, and 3 noncoding RNAs (ncRNAs).

Influence of gastrointestinal stress on autoinducer-2 activity of two Lactobacillus species.

Quorum sensing is a bacterial communication signalling system that regulates the expression of certain target genes with autoinducers in a cell density-dependent manner. The universal luxS-mediated quorum sensing using the autoinducer-2 (AI-2) signal is present in a wide variety of bacteria with only sparse information on probiotic lactobacilli. Effective probiotics should exhibit tolerance and adaptation to stress conditions typical of the GIT. Adhesion to human intestinal epithelial cells and competitive exclusion of pathogens are also considered important. The AI-2 signal system plays an important role in the response of probiotic lactobacilli to the surrounding environment. Intraspecies-related changes in quorum signalling in the GIT were determined by monitoring the AI-2 activity of two strains each of Lactobacillus rhamnosus and L. plantarum under various stress conditions. Modulation of the AI-2 activity of all the strains was induced by stress responses to pH, bile acid, temperature, osmotic pressure and starvation, and was both species- and strain-specific. AI-2 inhibition correlated with a reduction in the stress-related genes of L. rhamnosus. We therefore suggest that AI-2 quorum signalling of probiotic lactobacilli may represent one way of adapting to the host's ecosystem and of interacting within the intestinal environment.